Saftey Warning! Do you use Metal Air Caps? - The Unofficial BMW M5 Messageboard (m5board.com)

Ocean's M5 · 6th July 2005, 07:19

I have heard of cuple of times where there has been a Valve Stem Failure due to the use of Metal or Heavy Plastic Valve Stem Caps.

Don't Do It!

The centrifugal force generated by the Cap can not only Cause Tick Marks on the Rim of the wheel but more importantly, can cause Tire Failure.

I have installed "Shorty" valve stems with regular lightweight plastic caps to avoid being stranded.

6spd · 6th July 2005, 08:22

There are valvestem supports out there to help with this.
When buying rims look for the stem moved inward and flatter.

Good tip Ocean's

Need4Spd · 6th July 2005, 09:24

This is only using the heavy caps with the logos on them. The weight repeatedly bends the longer rubber stems and eventually causes them to crack. This could lead to catastrophic failure.

The lightweight stock metal caps are better than plastic ones because they serve as a backstop to the valve to keep it from leaking. They are light enough that they don't have the same tendency to bend the stems. When you get new tires and stems, get the short ones. The long ones really aren't necessary on the stock M5 wheels. (And go for rubber stems not the metal stems. I'm told by my tire guy that the metal ones tend to leak over time because they depend on a small O ring to seal the valve to the wheel. The O ring tends to shrivel over time and leak. The rubber ones should last at least as long as the tires. Always get new valves when getting new tires.)

Digi · 6th July 2005, 17:56

a solution to this problem is to replace the rubber stems with aluminum or chrome.

ELEVENS · 6th July 2005, 22:27

Does anyone know a source for the lightweight (aluminum?) valve stem caps that came on my 2003 as OEM? When I had new tires installed, they replaced the caps with the plastic ones, and really like the metal ones for the reason stated above (better seal).

Need4Spd · 6th July 2005, 23:41

Quote:

Does anyone know a source for the lightweight (aluminum?) valve stem caps that came on my 2003 as OEM?

Doesn't the dealer carry them?

KirklandM5 · 7th July 2005, 03:12

FWIW, Sasco Sports, a reseller of real race tires, use a metal valve stem cap with a rubber seal. They also advocate using metal valve stem.

Jim Dolan · 7th July 2005, 03:42

Here is a link to a comprehensve thread about this subject with photos of my wheels after the metal stems were replaced showing the telltale evidence of deflection against the rim.

Had to have a tow

Anzir · 7th July 2005, 05:56

Quote:

Originally Posted by Jim Dolan

Here is a link to a comprehensve thread about this subject with photos of my wheels after the metal stems were replaced showing the telltale evidence of deflection against the rim.

Had to have a tow

That's what I love about this board.. not a single topic that hasn't been discussed and documented!!

Andy Leeper · 7th July 2005, 17:07

Oh NO!!

Just purchased the M stems caps. Why?? Ok they looked cool. The dealership really should post a warning about this. $15 down the drain.

One thing that is interesting is that I bought the car used. Its a 2003 with 25K miles. I was having the wheels finished (there were some scuffs and small chips) and noticed the marks on the other side of the stem. This was before I replaced the rubber stock stems with the M caps. Any ideas to remedy this problem. I'll replace the M caps
ANDY